JavaScript mp3 decoder allows Firefox to play mp3 without flash • Hacker News Board

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#61

Post by nddrylliog » Fri, Jun 17, 2011, 6:33 PM UTC

tocomment wrote: post #60

How does this work? I didn't think JavaScript could read a file on a byte level.

Magnets heh. In JavaScript you have basically two options:

The legacy way is dealing with binary data as an ASCII String - effectively a string of bytes. This works but it's hella slow - probably because browsers didn't think we'd be using 67MB strings :)

The new way is with Typed Arrays: using an Uint8Array is pretty awesome, see the [Mozilla Developer Docs](https://developer.mozilla.org/en/JavaScript_typed_arrays).

Mozilla Firefox since version 4.0 allows to do XMLHttpRequests (xhr) to be retrieved directly as an ArrayBuffer, which you can then create an Uint8Array view on. Since Gecko 6.0 (Firefox 6.0), mozResponseByteArray is deprecated and they've implemented the new standard way: see https://developer.mozilla.org/En/XMLHttpRequest/Using_XMLHtt... for more details.

As for reading local files, the [W3C File API Draft](http://dev.w3.org/2006/webapi/FileAPI/) is implemented in Firefox 4.0 and Chrome 11+ as far as I can tell, and it also allows us to retrieve a binary string.

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#62

Post by jensnockert » Fri, Jun 17, 2011, 6:34 PM UTC

tocomment wrote: post #60

How does this work? I didn't think JavaScript could read a file on a byte level.

No, but it can read a string by codepoint. Which is almost the same.

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#63

Post by scythe » Fri, Jun 17, 2011, 6:48 PM UTC

Can this be made to work in Opera?

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#64

Post by evanrmurphy » Fri, Jun 17, 2011, 6:59 PM UTC

Hmm... 502 Bad Gateway. Can't wait to see this!

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#65

Post by jensnockert » Fri, Jun 17, 2011, 7:01 PM UTC

pistoriusp wrote: post #54

Would have been great if it worked on mobile Safari!

When it supports the Webkit Audio APIs, it will work. But it might be too slow on a phone. Even on a laptop it is a serious CPU hog.

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#66

Post by jensnockert » Fri, Jun 17, 2011, 7:07 PM UTC

evanrmurphy wrote: post #64

Hmm... 502 Bad Gateway. Can't wait to see this!

Sorry, yes. nddrylliog and romac are doing heroic efforts to keep the servers up. But we got slashdotted.

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#67

Post by jensnockert » Fri, Jun 17, 2011, 7:09 PM UTC

scythe wrote: post #63

Can this be made to work in Opera?

I don't know, I would guess that some sort of Audio API might be keeping it from running (like in Webkit).

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#68

Post by nddrylliog » Fri, Jun 17, 2011, 7:24 PM UTC

Firefox 4.0+ AND Chrome 13.0+ are supported.

However, Web Audio API doesn't seem enabled in Chrome 13 by default, just go to 'audio:flags', check "Web Audio", then click the "restart browser" button and it should work.

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#69

Post by nddrylliog » Fri, Jun 17, 2011, 7:32 PM UTC

evanrmurphy wrote: post #64

Hmm... 502 Bad Gateway. Can't wait to see this!

Back up! Enjoy :)

Re: JavaScript mp3 decoder allows Firefox to play mp3 without flash

#70

Post by seanalltogether » Fri, Jun 17, 2011, 7:41 PM UTC

nddrylliog wrote: post #58

mise wrote: post #51

Awesome! But... I'm not a JS guy. I can't contextualise this. How does this compare to HTML5 browser-based audio playing? Will this be a new way to make an audio button? Or does it go much deeper than that for JS apps?

From what I hear,the HTML5 tag implementation quality varies wildly. It hasn't been used much in production for desktop-targeted web apps. It is, however, quite popular on the iPlatforms, because you have no Flash there! As far as I can tell, jsmad is not going to replace the HTML5 audio tag on mobile devices. However, it does constitute a nice legal workaround for MP3 in desktop browsers such as Firefox. It gives ac…

At 50% cpu utilization this is very impractical outside tech demos.